Locking and holding device, principally for holding and handling of pattern plates, core masks, and the like

ABSTRACT

A locking and holding device holding and handling pattern plates, core masks and similar at molding machines in foundries. The device comprises a base plate (5) with a number of open grooves (6), which have parallel symmetry axes and are adapted to receive complementarily shaped locking studs (13), for example on a pattern plate (9). The base plate (5) is adapted to turn around a central, stationary bushing (8) projecting from the base plate, in which an upwards open recess has been made. The vertical symmetry axis of the recess is parallel to the vertical symmetry axes of the grooves in one turning position of the base plate (5). When the base plate (5) is turned away from this position, the pattern plate (9) cannot be removed from the base plate, because the wall of the recess secures the central stud (14) from the pattern plate.

The present invention relates to a locking and holding device,principally for holding and handling pattern plates, core masks and thelike for molding machines in foundries.

In connection with the production of disposable molds of sand there is aconsiderable need for being able to handle the comparatively heavy modelplates, which are steel plates, on which a pattern is mountedcorresponding to for example half the finished casting, in and out ofthe moulding chamber of the molding machine, which chamber is a closedspace, in which molding sand is filled for subsequent compression aroundthe pattern. The handling of the pattern plates outside the mold cavitycomprises also conveying the plates to the pattern store. The core masksshall be moved from a position outside the mold cavity in between themold parts produced in the mold cavity for placing one or several coresin the mold impressions made by the patterns in the molds. I any case itis a question of relatively complicated patterns of movement, combinedfrom swinging or rotary as well as translational movements. The patternof movement of the pattern plates and the core masks can usually bedissolved into three paths of movement at right angles to each other incombination with a turn around a line in a plane that is parallel to thedividing surface of the mold parts in the mold cavity.

Several examples are known of devices and apparatus for releasablesecuring of pattern plates and core masks and the handling of same.References can be made to the applicant's own patents (U.S. Pat. No.4,615,374 and GB-PS 2,164,282) as well as the applicant's own Danishapplication No. 4897/86.

The known apparatuses are under normal conditions fully capable ofholding pattern plates, core masks etc. as well as of handling them inspace between a position outside the mold cavity to the requisiteposition in the mold cavity and to deliver the parts conveyed byautomatic release by a locking device. The locking function depends,however, on locking arms transmitting the requisite locking force viahydraulic or pneumatic cylinders, a prerequisite that may fail. Apossible failure may cause serious damage to the handling apparatus andthe conveyed parts. In addition, the pneumatically or hydraulicallytransmitted locking forces complicate the handling apparatus and makesit more expensive.

It is the object of the present invention to provide a locking andholding device which on a purely mechanical basis ensures automaticholding of pattern plates, core masks, etc., once these parts have beencorrectly placed in the locking and holding device. The locking andholding device shall also move the conveyed parts three-dimensionallyand allow swinging the pattern plate, core mask etc. around a lineparallel with the surfaces of the parts.

This object is achieved according to the present invention with alocking and holding device of the kind referred to initially, andcharacterised in

a) that a base plate has been provided with a number of open grooves,which have parallel running symmetry axes and are adapted to receivecomplementary shaped locking studs on the part envisaged to be held,

b) that the base plate has been adapted to revolve around a central,stationary bushing projecting through the base plate,

c) that a recess has been provided in the projecting part of the bushingwith a U-shaped cross section in the vertical plane and with an upwardsfacing opening, whose symmetry axis in the locking/opening position runsparallel to the symmetry axes of the grooves, and

d) that on the part envisaged for holding there are projecting studsadapted to be received in the respective grooves in the base plate, anda central stud, which is adapted to engage in the recess in theprojecting, stationary bushing.

When the base plate has been moved to a position vertically under thestuds on the part envisaged for being conveyed and with the grooves inthe base plate in line with the studs, the junction can be performed byraising the base plate vertically, until the studs rest in the groovesin the base plate and the recess in the central bushing. By shifting thebase plate further vertically the conveyed part is raised free of itssupport and rests solely in the studs. A subsequent turning of the baseplate will render removal of the conveyed part impossible, because thesymmetry axes of the grooves are no longer parallel to the symmetry axisof the recess. The stud resting in the recess will therefore abuttagainst the wall of the recess and be locked in the central bushing. Inthis manner it has been ensured by simple means that the conveyed partcan only be placed in the locking and holding device (or be removed fromsame) when the base plate and the conveyed part and the studs placed onsame are in one position and one only in relation to each other. It istherefore possible to place pattern plates and core masks in an obliqueposition in relation to the horizontal plane, whereby mounting work andmaintenance is easier to carry out. The base plate can be suspended insuch a manner around the central bushing that a suitable friction isobtained when the pattern plate is turned manually, so that the patternplate stays immediately in the chosen angular position. Alternatively,it will be possible to adapt controlled turning mechanisms for turningand holding the base plate in position.

At an exemplary embodiment of a locking and holding device according tothe present invention the base plate is adapted with a generallyT-shaped section in the horizontal plane, where the root of the T meetsthe surface of the base plate.

In this manner it is ensured in a simple manner that the complementarilyshaped locking studs are secured in the base plate even if the lockingstuds are placed at one end surface of the conveyed part and thereby ata considerable distance from the center of gravity of the part. The barof the T of the locking studs will abutt against the side surfaces ofthe T and take up the moment of rotation caused by the center of gravityof the conveyed part.

According to the present invention the stationary bushing can befastened to a turntable, which may be adapted to turn around a verticalaxis and be moved vertically up and down along this axis.

In this manner it is made possible partly to exchange pattern plates orcore masks in due time before a pattern exchange in the so-called freepositions at the turntable, partly to have the possibility of raisingand lowering the base plate with the grooves in and out of engagementwith the studs on the part to be conveyed.

According to the present invention a number, preferably three, baseplates may be attached to the turntable around bushings that arestationary in relation to the turntable.

In this manner it is achieved that at any time there may be a patternplate or possibly a core mask in a position, from which by a purelytranslational movement it is moved in and out of the mold cavity of themolding machine. At the remaining pattern plates there may at the sametime be exchanges of pattern plates and or possibly preparatory worksuch as application of lubricants on the pattern, cleaning of filters inthe pattern plate, etc.

In the following the invention will be explained with reference to thedrawing, in which

FIG. 1 shows in perspective a changing turret, in which a locking andholding device according to the present invention is used,

FIG. 2a shows on an enlarged scale the locking and holding deviceaccording to the invention, and

FIG. 2b shows the locking and holding device according to the invention,but with the base plate turned away from the initial position shown inFIG. 2a.

The changing turret shown in FIG. 1 is placed next to the mold cavity(not shown) of a molding machine. The changing turret 1 consists of aprincipally triangular turntable 2, which is mounted in such a mannerthat it can revolve around a central column 3. The turntable 2 is alsoadapted to perform an up- and down movement along the column 3. In theexemplary embodiment shown in FIG. 1, bearings 4 are placed at thecorners of the turning disk 2. The bearings 4 serve as a hinged mountingof a base plate 5, in which grooves 6 and a central opening 7 have beenprovided, through which a cylindrical tube section 8 is passed, which isstationary in relation to the turntable 2. In the part of thecylindrical tube section 8 projecting from the base plate 5, a recess 15has been provided in the upper part. This creates an upward facing, opentrough, into which a cylindrical stud 14 can be passed from above with across section corresponding to the inside tube diameter.

In FIG. 1 in the lower right corner of the illustration a pattern plate9 is shown, which at the bottom is provided with wheels 10, running onrails 11. The pattern plate 9 carries a pattern 12. The pattern plate 9is moved translationally out and in of the mold cavity (not shown) byshifting along the rails 11.

When the pattern plate 9 is in the position shown in FIG. 1, the studs13,14 projecting from one end of the pattern plate are in a position inwhich they will be in line with the grooves 6,7 in the base plate 5,when the turntable 2 and the base plate 5 attached to the turntable havebeen turned to an area under the projecting studs 13,14.

By vertical shifting of the turntable 2 in relation to the pattern plate9 the studs 13 are moved into the respective groove 6, and the centralstud 14 is moved into the trough-shaped opening in the centrally placed,cylindrical tube section 8. By further raising the turntable 2, thepattern plate 9 will hang in the base plate 5 via the studs 13,14, andbe lifted free of the rails 11. It will then be possible to turn thepattern plate to arbitrary turning positions around the central column3, while at the same time turning around the bearing 4, so that thepattern plate can be in an oblique position in relation to thehorizontal.

In FIG. 2a the base plate 5 is shown on a larger scale. The base plateis oriented in such a manner that the vertical symmetry axes of thegrooves 6 shown in the drawing (sketched in dash-and-dot lines) areparallel with the vertical symmetry axis of the cylindrical tube section8. In addition, the grooves 6 and the cylindrical tube section 8 areplaced at generally equal horizontal distances. In this manner the baseplate 5 can be moved vertically upwards and in engagement with thesimilarly adapted and complementarily shaped studs 13 and 14 on one endface of the pattern plate 9.

When the studs 13 and 14 have been received in the respective groovesand openings, the base plate can be turned as described above around theaxis of the cylindrical tube section 8. That position is shown in FIG.2b.

In the turning position shown in FIG. 2b the pattern plate 9 cannot beremoved from the base plate 5, because the symmetry axes of the grooves6 are no longer parallel with the vertical symmetry axis through thecylindrical tube section 8, which remains stationary.

At the exemplary embodiment shown in the drawing, the studs 13 areprovided with an extension at the free end, whereby the studs will belocked in a position abutting against the rear side of groove 6 in thebase plate 5, which is T-shaped in horizontal section. In thisembodiment the pattern plate 9 is locked in the base plate 5, also inthe position in which the pattern plate 9 can be placed in or removedfrom the base plate 5 (FIG. 2a).

The present invention is not limited to just the features shown andspecified, and the locking and holding device provided by the inventioncan therefore also be used in connection with handling of other objectsthan the pattern plates and core masks set forth above.

I claim:
 1. A locking and holding device, suitable for holding andhandling a part, such as a pattern plate, core mask or the like, atmolding machines in foundries, said device comprising:a base platehaving a plurality of parallel open grooves, a central, stationarybushing projecting through said base plate and having a projecting partwith a recess comprising an upward facing opening, and said part to beheld having locking studs matched to, and adapted to be received by,said open grooves, a central stud provided on said part to be held whichis adapted to engage said recess in said stationary bushing, and whereinsaid base plate is adapted to rotate on said stationary bushing betweenunlocked position wherein said open grooves face upwards to receive saidpart and a locked position wherein said open grooves are rotated tothereby secure said part.
 2. The device according to claim 1, whereinthe grooves in the base plate have a generally T-shaped cross section ina horizontal plane with a narrow portion of the T-shaped grooveextending to the surface of the base plate.
 3. The device according toclaim 1, wherein the stationary bushing is fastened to a turntable,which is adapted to rotate on a vertical axis and move vertically up anddown along said vertical axis.
 4. The device according to claim 3,wherein a plurality of said bushings are fastened to said turntable eachcarrying a said base plate.
 5. The device according to claim 4, havingthree of said bushings fastened to said turntable.